https://doi.org/10.1140/epjd/e2003-00216-4
Photodissociation and photoionization of sodium coated C60 clusters
1
Laboratoire de Spectrométrie Ionique et Moléculaire (UMR 5579 du CNRS) ,
43 boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex, France
2
Laboratoire de Physique de la Matière Condensée et Nanostructures (UMR 5586 du CNRS) ,
43 boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex, France
Corresponding author: a pellarin@lasim.univ-lyon1.fr
Received:
3
March
2003
Revised:
7
May
2003
Published online:
17
July
2003
(C60)mNan clusters are produced in a tandem laser vaporization source and
analyzed by photoionization and photofragmentation time-of-flight mass spectroscopy. At
low sodium coverage, the special behavior of (C60)Nan clusters
is consistent with
a significant electron transfer from the first six adsorbed atoms towards each of the C60
fullerenes and an ionic-like bonding in this size range. However, the stability of the (C60)Na
cation is found much more pronounced than the one of (C60)Na
predicted to be a magic size under the hypothesis of a full charge transfer from the metal atoms to the C60 molecule. When
more sodium atoms are present, metal-metal bonds tend to become preponderant and control
the cluster properties. Relative to the number of sodium atoms, an odd-even alternation in
their stability is explained by the high dissociation rates for even-numbered clusters. The even
clusters evaporate neutral sodium atoms whereas odd ones prefer to evaporate Na2 molecules.
The hypotheses for the growth of a sodium droplet that does not wet the fullerene surface or
for the formation of a concentric metallic layer are discussed in the light of this study.
PACS: 36.40.Qv – Stability and fragmentation of clusters / 36.40.Mr – Spectroscopy and geometrical structure of clusters
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003